BASE INPUT ON FRF or RANDOM or TRANSIENT ANALYSIS

Jebunderscore
Jebunderscore Altair Community Member
edited October 2020 in Community Q&A

Hi to everyone, 

 how it is possible to assign a shift or an acceleration to the base of the structure for a FRF analysis? In particular, if i use SPCD on constrained DOF (SPC), i ve rigid body motion on SPCD dof.

as example: 

 

NODE 1: FIX CONSTRAINTS on 6 DOFs (SPC)

NODE 1: ACCELERATION on DOF 1 (SPCD)

 

I ve a rigid body motion on dof 1.

 

I want a structure fix on constraints but with an applied acce on one or more dofs (that are constrined)... like a Rensponse Spectrum Analysis.

 

thank you to all..

 

 

 

 

 

 

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Answers

  • Nachiket Kadu_22143
    Nachiket Kadu_22143 Altair Community Member
    edited May 2018
    Altair Forum User said:

    Hi to everyone, 

      how it is possible to assign a shift or an acceleration to the base of the structure for a FRF analysis? In particular, if i use SPCD on constrained DOF (SPC), i ve rigid body motion on SPCD dof.

    as example: 

     

    NODE 1: FIX CONSTRAINTS on 6 DOFs (SPC)

    NODE 1: ACCELERATION on DOF 1 (SPCD)

     

    I ve a rigid body motion on dof 1.

     

    I want a structure fix on constraints but with an applied acce on one or more dofs (that are constrined)... like a Rensponse Spectrum Analysis.

     

    thank you to all..

     

     

     

     

     

     

    Hi 

    Can you share any image regarding it?

  • Jebunderscore
    Jebunderscore Altair Community Member
    edited May 2018

    My case is like this:

     

     

    <?xml version="1.0" encoding="UTF-8"?>1.jpg

     

    I ve RIGID BODY MOTION on x direction

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited November 2020

    Hi,

     

    Here is a file where 6 Dofs of a node are constrained and SPCD is applied on the same node,

    Unable to find an attachment - read this blog

  • Nachiket Kadu_22143
    Nachiket Kadu_22143 Altair Community Member
    edited May 2018
    Altair Forum User said:

    My case is like this:

     

     

    <?xml version="1.0" encoding="UTF-8"?>1.jpg

     

    I ve RIGID BODY MOTION on x direction

    What response are you expecting?

  • Jebunderscore
    Jebunderscore Altair Community Member
    edited May 2018

    ok @Prakash Pagadala, i ve read this also on optistruct manual. How can I solve my problem?

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited May 2018

    @Jebunderscore

     

    Not sure what is happening with your model.

     

    If it is allowed, please share the model using the file transfer link

  • Jebunderscore
    Jebunderscore Altair Community Member
    edited May 2018

    my model is like your attached model. I want only the acce on constrained node, like a response spectrum. i ve solved my problem, i ve constrained the model on a portion near the applied acce. But there is a possibility to set an analysis (FRF ecc) with acce applied on the same constrained nodes?

    thank you .

  • Nachiket Kadu_22143
    Nachiket Kadu_22143 Altair Community Member
    edited May 2018
    Altair Forum User said:

    my model is like your attached model. I want only the acce on constrained node, like a response spectrum. i ve solved my problem, i ve constrained the model on a portion near the applied acce. But there is a possibility to set an analysis (FRF ecc) with acce applied on the same constrained nodes?

    thank you .

    Hi J

    I think what you did is, you gave spcd to all the nodes which had SPC because of which whole body will tend to move in that particular direction without opposition. You need to leave some nodes to oppose the SPCD motion. Release some node from SPCD and i think you can get answer to what you are looking for.

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